Flexible display apparatus having alignment mark and method of assembling the same

ABSTRACT

a window on a first surface of the flexible display panel; and a protective film on a second surface of the flexible display panel. The first alignment mark is aligned with a reference point of the window and with a reference point of the protective film.

This application claims priority to Korean Patent Application No.10-2018-0149274 filed on Nov. 28, 2018, and all the benefits accruingtherefrom under 35 U.S.C. § 119, the content of which in its entirety isherein incorporated by reference.

BACKGROUND 1. Field

Exemplary embodiments relate to a flexible display apparatus. Moreparticularly, exemplary embodiments relate to a flexible displayapparatus having an alignment mark used in a module-assembling processand a method of assembling the flexible display apparatus using thesame.

2. Description of the Related Art

A flat panel display device includes a liquid crystal display (“LCD”)device and an organic light emitting display (“OLED”) device. Theorganic light emitting display has an excellent luminance and viewingangle characteristics and does not include a separate back light ascompared with the liquid crystal display, so that the organic lightemitting display may be realized as an ultra-thin type of displaydevice. In the organic light emitting display device, an electroninjected through a cathode and an anode is recombined with holes in anorganic thin film to form an exciton. The organic light emitting displaydevice uses a phenomenon in which a light of a specific wavelength isgenerated by energy from the exciton.

A flexible display apparatus is being developed by forming displayareas, signal lines, etc. on a flexible substrate which includesmaterials such as flexible plastic materials.

SUMMARY

Exemplary embodiments provide a flexible display apparatus including analignment mark with improved visibility.

Exemplary embodiments provide a method of assembling a flexible displayapparatus using an alignment mark thereof with improved visibility.

According to an exemplary embodiment, a flexible display apparatusincludes a flexible display panel including a flexible substrateincluding a plastic layer, a display area of the flexible substrateincluding a thin film transistor, an organic light emitting layer, and asensor electrode on the flexible substrate, and a peripheral area of theflexible substrate adjacent to the display area, the peripheral areaincluding a first alignment mark in which respective portions of twometal layers are stacked; a window on a first surface of the flexibledisplay panel, the window including a reference point defined along thewindow, a transmissive window corresponding to the display area and alight shielding part corresponding to the peripheral area; and aprotective film on a second surface of the flexible display panel whichis opposite to the first surface thereof, the protective film includinga reference point defined along the protective film. The first alignmentmark is aligned with the reference point of the window and with thereference point of the protective film.

In an exemplary embodiment, the flexible display panel may furtherinclude a signal line which is in the display area and to which adisplay signal is provided, an extension area extended from theperipheral area in a direction away from the display area, and a pad inthe extension area, through which the display signal is transmitted fromoutside the flexible display panel to the signal line in the displayarea.

In an exemplary embodiment, the extension area of the flexible displaypanel may further include a second alignment mark in which respectiveportions of two metal layers are stacked, the two metal layers of thefirst alignment mark being different from the two metal layers of thesecond alignment mark.

In an exemplary embodiment, the flexible display apparatus may furtherinclude a flexible circuit board from which the display signal isprovided to the flexible display panel, and a circuit mounting filmconnected to the flexible circuit board and to the pad in the extensionarea the flexible display panel, and through which the display signalfrom the flexible circuit board is transmitted to the pad.

In an exemplary embodiment, the flexible display apparatus may furtherinclude a metal plate facing the second surface of the flexible displaypanel. The flexible display panel which is bent may dispose the metalplate between the extension area of the flexible display panel and theprotective film on the second surface of the flexible display panel.

In an exemplary embodiment, the second alignment mark may be alignedwith a reference point of each of the circuit mounting film, theflexible circuit board and the metal plate.

In an exemplary embodiment, the flexible display apparatus may furtherinclude a polarizing member between the flexible display panel and thewindow.

In an exemplary embodiment, the first alignment mark may be furtheraligned with a reference point of the polarizing member which is definedalong the polarizing member.

In an exemplary embodiment, the display area of the flexible displaypanel may include a folding axis about which the flexible display panelis bendable.

In an exemplary embodiment, the first alignment mark and the secondalignment mark may each include a portion of a first metal layer, aportion of a second metal layer, a portion of a third metal layer and aportion of a fourth metal layer sequentially which are sequentiallystacked on the flexible substrate.

In an exemplary embodiment, the thin film transistor may include a gateelectrode and a source electrode, the sensor electrode may include afirst touch electrode and a second touch electrode, the gate electrode,the first alignment mark and the second alignment mark may each includerespective portions of a same first metal layer, the source electrode,the first alignment mark and the second alignment mark may each includerespective portions of a same second metal layer, the first touchelectrode, the first alignment mark and the second alignment mark mayeach include respective portions of a same third metal layer, and thesecond touch electrode, the first alignment mark and the secondalignment mark may each include respective portions of a same fourthmetal layer.

According to an exemplary embodiment, a method of assembling a flexibledisplay apparatus includes providing a flexible display panel includinga flexible substrate including a plastic layer, a display area of theflexible substrate including a thin film transistor, an organic lightemitting layer, and a sensor electrode on the flexible substrate, and aperipheral area of the flexible substrate adjacent to the display area,the peripheral area including a first alignment mark in which respectiveportions of two metal layers are stacked. The method may includeattaching a polarizing member on a first surface of the flexible displaypanel using the first alignment mark, attaching a window on the firstsurface of the flexible display panel using the first alignment mark,and attaching a protective film on a second surface of the flexibledisplay panel using the first alignment mark.

In an exemplary embodiment, the attaching the polarizing member mayinclude providing the polarizing member on the flexible display paneland generating an alignment image of the first alignment mark by usinglight which is transmitted or reflected at an area of the flexibledisplay at which the first alignment mark is provided, and aligning thefirst alignment mark and a reference point of the polarizing memberusing the alignment image of the first alignment mark.

In an exemplary embodiment, the attaching the window may includeproviding the window on the flexible display panel and generating analignment image of the first alignment mark by using light which isreflected at an area of the flexible display at which the firstalignment mark is provided, and aligning the first alignment mark and areference point of the window using the alignment image of the firstalignment mark.

In an exemplary embodiment, the attaching the protective film mayinclude providing the protective film on the flexible display panel andgenerating an alignment image of the first alignment mark by using lightwhich is reflected at an area of the flexible display at which the firstalignment mark is provided, and aligning the first alignment mark and areference point of the protective film using the alignment image of thefirst alignment mark.

In an exemplary embodiment, the flexible display panel further mayinclude a signal line which is in the display area and to which adisplay signal is provided, an extension area extended from theperipheral area in a direction away from the display area, a pad in theextension area, through which the display signal is transmitted fromoutside the flexible display panel to the signal line in the displayarea and a second alignment mark which is in the extension area and inwhich respective portions of two metal layers are stacked, the two metallayers of the first alignment mark being different from the two metallayers of the second alignment mark. The method may further includeattaching a circuit mounting film on the extension area using the secondalignment mark, and attaching a metal plate on the protective film usingthe second alignment mark.

In an exemplary embodiment, the attaching the circuit mounting film mayinclude providing the circuit mounting film on the flexible displaypanel and generating an alignment image of the second alignment mark byusing light which is transmitted or reflected at an area of the flexibledisplay at which the second alignment mark is provided, and aligning thesecond alignment mark and the circuit mounting film using the alignmentimage of the second alignment mark.

In an exemplary embodiment, the attaching the metal plate may includeproviding the metal plate on the flexible display panel and generatingan alignment image of the second alignment mark by using light which isreflected at an area of the flexible display at which the secondalignment mark is provided, and aligning the second alignment mark witha reference point of the metal plate using the alignment image of thesecond alignment mark.

In an exemplary embodiment, the method may further include bending theextension area of the flexible display panel having the metal plateattached to the protective film, toward the metal plate, generating analignment image of the second alignment mark by using light which isreflected at an area of the flexible display at which the secondalignment mark is provided, and aligning the second alignment mark witha bending reference point using the alignment image of the secondalignment mark.

According to one or more of the exemplary embodiments, the flexibledisplay apparatus includes alignment marks of a stacked structure ofrespective portions of a plurality of metal layers fabricated from aplurality of metal layers used in manufacturing processes of the thinfilm transistor and the touch sensor. In the module-assembling processesof the flexible display apparatus, a clear alignment mark image may beobtained by the alignment mark having a structure in which a pluralityof metal layers is stacked. Therefore, an accuracy of themodule-assembling processes may be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the invention will becomemore apparent by describing in detailed exemplary embodiments thereofwith reference to the accompanying drawings, in which:

FIG. 1 is a top plan view illustrating an exemplary embodiment of aflexible display panel;

FIG. 2 is a cross-sectional view illustrating the flexible display paneltaken along line I-I′ in FIG. 1;

FIGS. 3 to 5 are cross-sectional views illustrating structures of aflexible display panel in an exemplary embodiment of a method ofmanufacturing the flexible display panel of FIG. 2;

FIGS. 6A and 6B are respectively embodiments of a front plan view and aback plan view of a flexible display apparatus;

FIG. 7A is a cross-sectional view illustrating the flexible displayapparatus taken along line a-a′ in FIG. 6A;

FIG. 7B is a cross-sectional view illustrating the flexible displayapparatus taken along line b-b′ in FIG. 6B; and

FIGS. 8 to 12 are cross-sectional views illustrating structures of aflexible display apparatus in an exemplary embodiment of a method ofmodule-assembling the flexible display apparatus of FIG. 6A and 6B.

DETAILED DESCRIPTION

The invention now will be described more fully hereinafter withreference to the accompanying drawings, in which various embodiments areshown. This invention may, however, be embodied in many different forms,and should not be construed as limited to the embodiments set forthherein. Rather, these embodiments are provided so that this disclosurewill be thorough and complete, and will fully convey the scope of theinvention to those skilled in the art. Like reference numerals refer tolike elements throughout.

It will be understood that when an element is referred to as beingrelated to another element such as being “on” another element, it can bedirectly on the other element or intervening elements may be presenttherebetween. In contrast, when an element is referred to as beingrelated to another element such as being “directly on” another element,there are no intervening elements present.

It will be understood that, although the terms “first,” “second,”“third” etc. may be used herein to describe various elements,components, regions, layers and/or sections, these elements, components,regions, layers and/or sections should not be limited by these terms.These terms are only used to distinguish one element, component, region,layer or section from another element, component, region, layer orsection. Thus, “a first element,” “component,” “region,” “layer” or“section” discussed below could be termed a second element, component,region, layer or section without departing from the teachings herein.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a” “an,” and “the” are intended to include the pluralforms, including “at least one,” unless the content clearly indicatesotherwise. “At least one” is not to be construed as limiting “a” or“an.” “Or” means “and/or.” As used herein, the term “and/or” includesany and all combinations of one or more of the associated listed items.It will be further understood that the terms “comprises” and/or“comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top,” may be used herein to describe one element's relationship toanother element as illustrated in the Figures. It will be understoodthat relative terms are intended to encompass different orientations ofthe device in addition to the orientation depicted in the Figures. Forexample, if the device in one of the figures is turned over, elementsdescribed as being on the “lower” side of other elements would then beoriented on “upper” sides of the other elements. The exemplary term“lower,” can therefore, encompasses both an orientation of “lower” and“upper,” depending on the particular orientation of the figure.Similarly, if the device in one of the figures is turned over, elementsdescribed as “below” or “beneath” other elements would then be oriented“above” the other elements. The exemplary terms “below” or “beneath”can, therefore, encompass both an orientation of above and below.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

Hereinafter, the invention will be explained in detail with reference tothe accompanying drawings.

FIG. 1 is a top plan view illustrating an exemplary embodiment of aflexible display panel. FIG. 2 is a cross-sectional view illustratingthe flexible display panel taken along line I-I′ in FIG. 1.

Referring to FIG. 1, the flexible display panel 100 may include a firstarea Al and a second area A2 which is adjacent to the first area A1.

The first area A1 may include a display area DA and a peripheral area PAwhich is adjacent to the display area DA.

The display area DA may include a folding axis FA defined in a centralarea thereof, and the display area DA may be foldable along the foldingaxis FA. The flexible display panel 100 and/or components thereof mayalso be foldable or bendable about the folding axis FA. Therefore, afirst display area DP1 and a second display area DP2 of the display areaDA may be respectively defined at opposing sides of the folding axis FA.

The display area DA is an area at which an image is displayed. Aplurality of signal lines and a plurality of pixels which are connectedto corresponding ones of the plurality of signal lines may be arrangedin the display area DA.

The peripheral area PA is an area which is adjacent to an edge portionof the display area DA. The peripheral area PA is an area at which animage is not displayed. The peripheral area PA may define an outermostregion of the flexible display panel 100. A driver circuit (not shown)for generating signals which are provided to and transmitted through theplurality of signal lines arranged in the display area DA, may bedisposed in the peripheral area PA. That is, a driving display signal, acontrol display signal, etc. may be provided from the outside thedisplay area DA by the driver circuit, and to the pixels in the displayarea DA via the signal lines.

In one exemplary embodiment, a first alignment mark AM1 provided inplural (also hereinafter, referred to as a plurality of first alignmentmarks AM1 or first alignment marks AM1) and used in a module-assemblingprocess of the flexible display panel 100, may be disposed in theperipheral area PA. The plurality of first alignment marks AM1 may beused for a bonding alignment and a bonding accuracy test between theflexible display panel 100 and various members of a flexible displayapparatus during the module-assembling process. The members of theflexible display apparatus which may be attached to the flexible displaypanel 100 include film members of the flexible display apparatus.

The plurality of first alignment marks AM1 may have various shapes andmay be disposed at various positions within the peripheral area PA. Asshown in FIG. 1, each one of the first alignment marks AM1 within agroup of first alignment marks AM1 may have a discrete shape in the topplan view. Within a group, the plurality of first alignment marks AM1may be spaced apart from each other.

The second area A2 may be an extension area which extends from a firstside portion of the peripheral area PA. The second area A2 may beconsidered a portion of the peripheral area PA, without being limitedthereto. The second area A2 may include a line area LA and a pad areaPDA. The second area A2 together with the peripheral area PA may definea non-display area of the flexible display panel 100.

The line area LA may include arranged therein a plurality of fan-outsignal lines connected to signal lines arranged in the display area DA.

The pad area PDA may include arranged therein a plurality of padsconnected to the fan-out signal lines. That is, signals such as adriving signal, a control signal, etc. may be provided to the pads inthe pad area PDA from outside the flexible display panel 100. In anexemplary embodiment, the signals may be provided from the pads in thepad area PDA, through the fan-out signal lines in the line area LA, andto the signal lines arranged in the display area DA. Pixels in thedisplay area DA may be controlled or driven to display an image with thesignals provided from the fan-out signal lines in the line area LA.

In one exemplary embodiment, a second alignment mark AM2 provided inplurality (hereinafter, referred to as a plurality of second alignmentmarks AM2 or second alignment marks AM2) and used in themodule-assembling process of the flexible display panel 100, may bedisposed in the second area A2.

The plurality of second alignment marks AM2 are used as a referencepoint with which a device external to the flexible display panel 100(hereinafter, referred to as an external device) is coupled to a padarea PDA of the flexible display panel 100. In addition, the pluralityof second alignment marks AM2 may be used as the reference point withwhich a position of the external device coupled to the flexible displaypanel 100 is indicated in determining if such position is correct.

In an exemplary embodiment of a bending process during amodule-assembling process, the second area A2 of the flexible displaypanel 100 is bent toward a back surface of the first area A1. Theplurality of second alignment marks AM2 may be used as a reference pointwith which a bending alignment and a bending accuracy in bending thesecond area A2 are determined.

The plurality of second alignment marks AM2 may have various shapes andmay be disposed at various positions within the second area A2. Each oneof the second alignment marks AM2 may have a discrete shape in the topplan view. In an exemplary embodiment, for example, the plurality ofsecond alignment marks AM2 may be each disposed at an edge portion ofthe second area A2.

According to one exemplary embodiment, each one alignment mark among theplurality of first alignment marks AM1 and the plurality of secondalignment marks AM2 may include at least two metal layers each includinga metal material.

Referring to FIG. 2, the flexible display panel 100 may include acolored flexible substrate 110 including the display area DA, theperipheral area PA, and the second area A2.

The colored flexible substrate 110 may include a first transparent layer101, a colored layer 102 and a second transparent layer 103 which aresequentially stacked. The colored layer 102 may include an opaquematerial filled therein. Each of the first transparent layer 101, thecolored layer 102 and the second transparent layer 103 may include aplastic layer including a plastic material. In an exemplary embodiment,for example, the plastic layer may include or be formed of a materialselected from among polyimide (“PI”), polyethylene naphthalate (“PEN”),polyethylene terephthalate (“PET”), polyarylate (“PAR”), polycarbonate(“PC”), polyetherimide (“PEI”), polyethersulfone (“PS”), and the like.The first transparent layer 101, the colored layer 102 and the secondtransparent layer 103 including the plastic layer may hereinafter bereferred to as a first transparent plastic layer 101, a colored plasticlayer 102 and a second transparent plastic layer 103, respectively.

The flexible display panel 100 may include a thin film transistor TFT,an organic light emitting diode OLED as a light-emitting element, atouch sensor electrode TSE, a first alignment mark AM1 and a secondalignment mark AM2. The touch sensor electrode TSE may include a firsttouch electrode XE and a second touch electrode YE. Each one of theaforementioned elements may be provided in plural within the flexibledisplay panel 100.

The flexible display panel 100 may include a buffer layer 111, a gateinsulating layer 113, a first interlayer insulating layer 116, a firstplanarization layer 121, a pixel definition layer 122, an encapsulationmember 150, a second planarization layer 160, a second interlayerinsulating layer 170, and a passivation layer 180.

The thin film transistor TFT includes an active pattern AC, a gateelectrode GE, a source electrode SE, and a drain electrode DE. The gateelectrode GE may include or be formed from a first metal layer, and thesource electrode SE and the drain electrode DE may be formed from asecond metal layer. The source electrode SE and the drain electrode DEmay be formed from a same one second metal layer to be disposed in asame layer of the flexible display panel 100 among layers disposed onthe colored flexible substrate 110.

The organic light emitting diode OLED may include a first pixelelectrode PE1, a light emitting layer EL, and a second pixel electrodePE2. The first pixel election PE1 is connected to the drain electrode DEof the thin film transistor TFT at or through a contact hole in thefirst planarization layer 121. The light emitting layer EL is disposedon the first pixel electrode PE1 exposed through an opening in the pixeldefinition layer 122. The second pixel electrode PE2 is disposed on thelight emitting layer EL and overlaps with the first pixel electrode PE1.

The encapsulation member 150 may cover a front surface of the displayarea DA and extend from the display area DA to cover both the peripheralarea PA and the second area A2. However, in an alternative exemplaryembodiment, the encapsulation member 150 may not cover the pad area PDAin the second area A2.

The first touch electrode XE may be provided or formed in the displayarea DA. The first touch electrode XE may be a first electrode of atouch sensor for sensing a touch from outside the flexible display panel100. The first touch electrode XE may include or be formed from a thirdmetal layer.

The second touch electrode YE may be a second electrode of the touchsensor. The second touch electrode YE may include or be formed from afourth metal layer.

The first alignment mark AM1 may be disposed in the peripheral area PA.The first alignment mark AM1 includes a first layer MG1 formed from asame first metal layer as the gate electrode GE, a second layer MS1formed from a same second metal layer as the source electrode SE, athird layer MX1 formed from a same third metal layer as the first touchelectrode XE and a fourth layer MY1 formed from a same fourth metallayer as the second touch electrode XY. That is, the various layers ofthe first alignment mark AM1 and the corresponding electrodes describedabove, are respectively portions of a same material layer, so as to bedisposed in a same layer of the flexible display panel 100 among layersprovided on the colored flexible substrate 110.

In one exemplary embodiment, the first alignment mark AM1 may have astructure in which at least two portions among the first through fourthmetal layers are stacked.

The second alignment mark AM2 may be disposed in the second area A2. Thesecond alignment mark AM2 includes a first layer MG2 formed from a samefirst metal layer as the gate electrode GE, a second layer MS2 formedfrom a same second metal layer as the source electrode SE, a third layerMX2 formed from a same third metal layer as the first touch electrode XEand a fourth layer MY2 formed from a same fourth metal layer as thesecond touch electrode XY. That is, the various layers of the secondalignment mark AM2 and the corresponding electrodes described above, arerespectively portions of a same material layer, so as to be disposed ina same layer of the flexible display panel 100 among layers provided onthe colored flexible substrate 110.

In one exemplary embodiment, the second alignment mark AM2 may have amulti-layer structure in which at least two portions among the first tofourth metal layers are stacked.

FIGS. 3 to 5 are cross-sectional views illustrating structures of aflexible display panel in an exemplary embodiment of a method ofmanufacturing the flexible display panel of FIG. 2.

Referring to FIG. 3, the colored flexible substrate 110 may include afirst transparent plastic layer 101, a colored plastic layer 102 and asecond transparent plastic layer 103 which are sequentially stacked.

A buffer layer 111 is provided or formed on the colored flexiblesubstrate 110. In an exemplary embodiment, for example, the buffer layer111 may be provided or formed by various methods such as a chemicalvapor deposition (“CVD”) or a sputtering using silicon oxide, siliconnitride, silicon oxynitride, or the like.

A thin film transistor TFT, the first layer MG1 and the second layer MS1of a first alignment mark AM1 and the first layer MG2 and the secondlayer MS2 of a second alignment mark AM2 are provided or formed on thebuffer layer 111.

The thin film transistor TFT may include an active pattern AC, a gateelectrode GE, a source electrode SE, and a drain electrode DE.

A semiconductor layer may be provided or formed on the buffer layer 111.In an exemplary embodiment, for example, a semiconductor layer may beprovided or formed by providing or forming a layer including asilicon-containing material, an oxide semiconductor material or thelike, on an entire surface of the buffer layer 111, and then patternedthe layer to form a semiconductor layer. When a semiconductor layer isprovided or formed using the silicon-containing material, an amorphoussilicon layer may be provided or formed on the entire surface of thebuffer layer 111 and crystallized to form a polycrystalline siliconlayer. The semiconductor layer is patterned to form an active patternAC. Each of opposing sides of the active pattern AC may be doped withimpurities to form the active pattern AC including a source area, adrain area, and a channel area which is between the source and drainareas.

A gate insulating layer 113 may be provided or formed on the activepattern AC. In an exemplary embodiment, for example, the gate insulatinglayer 113 may be provided or formed using silicon oxide, siliconnitride, silicon oxynitride, or the like.

A first metal layer is provided or formed on the gate insulating layer113 and patterned to provide or form a gate electrode GE, a first layerMG1 of the first alignment mark AM1 and a first layer MG2 of the secondalignment mark AM2.

A first interlayer insulating layer 116 may be provided or formed on thegate electrode GE, the first layer MG1 and the first layer MG2. In anexemplary embodiment, for example, the first interlayer insulating layer116 may include or be formed of silicon oxide, silicon nitride, siliconoxynitride, or the like.

A plurality of contact holes exposing the semiconductor layer may beprovided or formed in the first interlayer insulating layer 116 and thegate insulating layer 113. In an exemplary embodiment, for example, thecontact holes may respectively expose a source area and a drain area ofthe active pattern AC.

A second metal layer is provided or formed on the first interlayerinsulating layer 116. The second metal layer is patterned to form asource electrode SE connected to the source area, a drain electrode DEconnected to the drain area, a second layer MS1 of the first alignmentmark AM1 and a second layer MS2 of the second alignment mark AM2.

Referring to FIG. 4, a first planarization layer 121 is provided orformed on the source electrode SE and the drain electrode DE. The firstplanarization layer 121 may include an organic material such as anacrylic resin, an epoxy resin, a polyimide resin, and a polyester resin.The first planarization layer 121 may be provided or formed only in thedisplay area DA.

A first pixel electrode PE1 is provided or formed on the firstplanarization layer 121. The first pixel electrode PE1 may be connectedto the drain electrode DE of the thin film transistor TFT through acontact hole provided or formed in the first planarization layer 121.

A pixel definition layer 122 is provided or formed on the first pixelelectrode PH. The pixel definition layer 122 may be provided or formedonly in the display area DA. In an exemplary embodiment, for example,the pixel definition layer 122 may include or be formed of a polyimideresin, a photoresist, an acryl resin, a polyamide resin, a siloxaneresin, or the like. The pixel definition layer 122 may be patterned toprovide or form an opening exposing a portion of the first pixelelectrode PE1.

A light emitting layer EL is provided or formed on the first pixelelectrode PE1 in the opening. The light emitting layer EL may include ahole injection layer (“HIL”), a hole transport layer (“HTL”), anelectron transport layer (“ETL”), an organic light emitting layer(“EML”), and an electron injection layer (“EIL”).

A second pixel electrode PE2 is provided or formed on light emittinglayer EL. The second pixel electrode PE2 may be provided or formedentirely in the display area DA.

Referring to FIG. 5, an encapsulation member 150 is provided or formedon the second layer MS1, the second layer MS2 and the organic lightemitting diode OLED. The encapsulation member 150 may have a structurein which an inorganic layer and an organic layer are alternatelystacked. The encapsulation member 150 may protect the organic lightemitting diode OLED from moisture. The encapsulation member 150 may beprovided or formed in the peripheral area PA and the second area A2.Alternatively, the encapsulation member 150 may not be provided orformed in the peripheral area PA or the second area A2.

A second planarization layer 160 is provided or formed on theencapsulation member 150. The second planarization layer 160 may beprovided or formed entirely in the display area DA, the peripheral areaPA, and the second area A2.

A third metal layer is provided or formed on the second planarizationlayer 160. The third metal layer is patterned to form a first touchelectrode XE, a third layer MX1 of a first alignment mark AM1, and athird layer MX2 of a second alignment mark AM2.

A second interlayer insulating layer 170 is provided or formed on thefirst touch electrode XE, the third layer MX1 and the third layer MX2.

A fourth metal layer is provided or formed on the second interlayerinsulating layer 170. The fourth metal layer may be patterned to provideor form a second touch electrode

YE, a fourth layer MY1 of a first alignment mark AM1 and a fourth layerMY2 of a second alignment mark AM2.

A passivation layer 180 is provided or formed on the second touchelectrode YE, the fourth layer MY1 and the fourth layer MY2. Thepassivation layer 180 may be provided or formed entirely in the displayarea DA, the peripheral area PA, and the second area A2 of the coloredflexible substrate 110.

The flexible display panel 100 according to the exemplary embodiment maybe completed by the above manufacturing processes.

The flexible display panel 100 according to the exemplary embodiment mayinclude the first alignment mark AM1 and the second alignment mark AM2in each of which at least portions of two metal layers are stacked.

FIGS. 6A and 6B are respectively embodiments of a front plan view and aback plan view of a flexible display apparatus. FIG. 7A is across-sectional view illustrating the flexible display apparatus takenalong line a-a′ in FIG. 6A. FIG. 7B is a cross-sectional viewillustrating the flexible display apparatus taken along line b-b′ inFIG. 6B.

Referring to FIGS. 6A to 7B, the flexible display apparatus 1000 mayinclude a flexible display panel 100, a polarizing member 200, a circuitmounting film 310, a flexible circuit board 330, a window member 400, aprotective film 500 and a metal plate 600. The flexible displayapparatus 1000 and/or components thereof may be disposed in a planedefined by a first direction and a second direction which cross eachother. In FIG. 6A and 6B, for example, the horizontal direction and thevertical direction may variously represent the first direction and/orthe second direction. A thickness of the flexible display apparatus 1000and/or components thereof may be defined along a third direction whichcrosses each of the first direction and the second direction. In FIGS.7A and 7B, for example, the vertical direction may represent a thicknessdirection, while the horizontal direction may variously represent thefirst direction and/or the second direction.

The flexible display panel 100 may include substantially the samecomponents as those of the flexible display panel according to theprevious embodiments described with reference to FIGS. 1 and 2.

The flexible display panel 100 may include a first area Al and a secondarea A2.

The first area A1 may include a display area DA and a peripheral area PAwhich is adjacent to the display area DA. The peripheral area PA maysurround the display area DA in a top plan view, without being limitedthereto.

The display area DA includes a folding axis FA defined at a central areaof the display area DA, and a first display area DP1 and a seconddisplay area DP2 may be defined respectively on opposing sides of thefolding axis FA. The display area DA is an area at which an image isdisplayed, and in which a plurality of signal lines and a plurality ofpixels may be arranged.

The peripheral area PA is an area adjacent to an edge portion of thedisplay area DA. A driver circuit (not shown) for generating signalswhich are provided to the plurality of signal lines arranged in thedisplay area DA, may be disposed in peripheral area PA.

In one exemplary embodiment, a plurality of first alignment marks AM1used in a module-assembling process of the flexible display panel 100may be disposed in the peripheral area PA. The plurality of firstalignment marks AM1 may be used for a bonding alignment and a bondingaccuracy test between the flexible display panel 100 and variousattachment members of the flexible display apparatus 1000, such as filmmembers of the flexible display apparatus 1000, during themodule-assembling process.

The plurality of first alignment marks AM1 may have various shapes andmay be disposed at various positions within the peripheral area PA.

The second area A2 may be an extension area of the flexible displaypanel 100 which extends from a first side portion of the peripheral areaPA. The second area A2 may include a pad area PDA. The pad area PDA mayinclude a plurality of pads, and the plurality of pads may be connectedto the circuit mounting film 310.

In one exemplary embodiment, a plurality of second alignment marks AM2used in the module assembling process of the flexible display panel 100may be disposed in the second area A2.

The plurality of second alignment marks AM2 are used as a referencepoint for accurately coupling an external device to a pad area PDA ofthe flexible display panel 100. In addition, the plurality of secondalignment marks AM2 may be used as the reference point for checkingwhether the external device is coupled to the flexible display panel 100at a correct position.

Referring to FIGS. 6A and 6B, the flexible display panel 100 having thecircuit mounting film 310 and the flexible circuit board 330 coupledthereto is bendable at the second area A2. The flexible display panel100 may be bendable at a boundary between the first area A1 and thesecond area A2, without being limited thereto. In an exemplaryembodiment of a bending process of a module-assembling process, theflexible display panel 100 which is bent disposes the second area A2facing the back surface of the first area A1. The plurality of secondalignment marks AM2 may be used to check a bending alignment and abending accuracy related to a position of the second area A2 relative tothe first area A1.

The plurality of second alignment marks AM2 may have various shapes andmay be disposed at various positions within the second area A2. In anexemplary embodiment, for example, the plurality of second alignmentmarks AM2 may be disposed at an edge portion of the second area A2.

The plurality of first alignment marks AM1 and the plurality of secondalignment marks AM2 may each have a structure in which portions of atleast two metal layers are stacked along a thickness direction of theflexible display panel 100, as described with reference to FIG. 2.

Referring to FIG. 7A, the polarizing member 200 is disposed on a firstsurface of the flexible display panel 100. The first surface maycorrespond to a front surface of the flexible display panel 100 as alight emitting surface thereof. The polarizing member 200 may beattached to the first surface of the flexible display panel 100 using anadhesive film member.

The circuit mounting film 310 may include a first end portion mounted onand/or connected to the plurality of pads formed in the second area A2of the flexible display panel 100, and a second end portion which isopposite to the first end portion and connected to the flexible circuitboard 330.

The flexible circuit board 330 may be connected at a second end thereofto the second end portion of the circuit mounting film 310, and theflexible circuit board 300 may be connected at a first end thereof to anexternal graphics device (not shown).

The window member 400 is disposed on the first surface of the polarizingmember 200. The window member 400 is a film material and may be attachedto the polarizing member 200 using an adhesive film member. The windowmember 400 includes a light shielding part 410 for blocking a lightgenerated from the flexible display panel 100 and a transmission window430 for transmitting the light. The light shielding part 410 maycorrespond to the peripheral area PA of the flexible display panel 100.The transmission window 430 may correspond to the display area DA of theflexible display panel 100.

Referring to FIGS. 7A and 7B, the protective film 500 is disposed on asecond surface of the flexible display panel 100 which is opposite tothe first surface of the flexible display panel 100. The second surfacemay correspond to a back surface which is opposite to the front surfaceof the flexible display panel 100. The protective film 500 may protectthe flexible display panel 100 from external impacts by including acushioning material. The protective film 500 may be attached to thesecond surface of the flexible display panel 100 by an adhesive filmmember.

The metal plate 600 is disposed on the protective film 500 disposed onthe second surface of the flexible display panel 100. The metal plate600 may serve as a frame to maintain a rigidity or an overall shape ofthe flexible display panel 100. The metal plate 600 may be attached tothe protective film 500 by an adhesive film member.

Referring to FIGS. 6B and 7B, the metal plate 600 may include a firstsurface attached to the protective film 500 and a second surfaceopposite to the first surface. Referring to FIG. 7A, the flexibledisplay panel 100 which is not bent disposes the second surface of themetal plate 600 exposed outside the flexible display apparatus 1000. Theflexible display panel 100 which is bent disposes the second area A2thereof facing the second surface of the metal plate 600. The flexibledisplay panel 100 which is bent also disposes the second area A2 thereoffacing the first area A1, as shown in FIG. 6B and 7B. The circuitmounting film 310 and the flexible circuit board 330 which are connectedto the second area A2 of the flexible display panel 100 may be disposedfacing the second surface of the metal plate 600.

FIGS. 8 to 12 are cross-sectional views illustrating structures of aflexible display apparatus in an exemplary embodiment of a method ofmodule-assembling a flexible display apparatus.

FIG. 8 is a cross-sectional view illustrating the flexible displayapparatus taken along line II-II′ in FIG. 6A, according to a firstassembling process.

Referring to FIG. 8, the module-assembling process may include using acamera 810 and a lamp 830. The camera 810 generates an alignment imageusing a light generated from the lamp 830. The lamp 830 irradiates anarea of the flexible display panel 100 in which an alignment mark isdisposed to identify and determine a location of the alignment markdisposed on the flexible display panel 100. The light from the lamp 830may be incident to the area of the flexible display panel 100 in whichan alignment mark is disposed and subsequently transmitted or reflectedbased on interaction of the light relative to the alignment mark andsurrounding area of the flexible display panel 100.

In the first assembling process, the polarizing member 200 may bealigned and attached on the flexible display panel 100 using a firstalignment mark AM1 disposed in the flexible display panel 100. Theportions of various metal layers within the first alignment mark AM1 areshown as solid line bars in FIG. 8.

The camera 810 may be disposed on the flexible display panel 100 and thelamp 830 may be disposed on a lower portion of the flexible displaypanel 100. In this case, the camera 810 may generate a first alignmentimage using the light of the lamp 830 transmitted through the flexibledisplay panel 100.

In one exemplary embodiment, a substrate of the flexible display panel100 may be flexible and may include a plastic layer which is colored.When the lamp 830 is disposed at the lower portion of the flexibledisplay panel 100, the light may be reflected by a material included inand filling the plastic layer which is colored. Therefore, the lightincident on the camera 810 decreases, and thus a sharpness of thealignment image may be degraded.

However, according to one or more exemplary embodiment, the firstalignment mark AM1 has a structure in which a plurality of metal layersis stacked, so that a sharpness of the alignment image corresponding tothe first alignment mark AM1 may be increased. Light may be reflected bythe first alignment mark AM1, to increase sharpness of the alignmentimage.

Alternatively, although not shown in figures, the lamp 830 may bedisposed at an upper portion of the flexible display panel 100, such ascorresponding to the camera 810. In this case, the camera 810 maygenerate a first alignment image using the light reflected from theflexible display panel 100.

In one exemplary embodiment, the first alignment mark AM1 has astructure in which portions of a plurality of metal layers are stacked,so that the sharpness of the alignment image is increased by generationof reflected light by the metal layers.

The first alignment mark AM1 and a first reference point RP1 of thepolarizing member 200 are aligned to be adjacent to each other, usingthe first alignment image generated by the camera 810. While the firstreference point RP1 of the polarizing member 200 is aligned with thefirst alignment mark AM1, the polarizing member 200 may be coupled tothe flexible display panel 100. The first reference point RP1 of thepolarizing member 200 may be defined at a location along the polarizingmember 200. The first reference point RP1 of the polarizing member 200may be an edge area of the polarizing member 200.

In one exemplary embodiment, the polarizing member 200 is attached onthe first surface of the flexible display panel 100, and then a processof attaching the circuit mounting film 310 and the flexible circuitboard 330 may be performed.

Referring to FIG. 6A, in an assembling process of the circuit mountingfilm 310, the circuit mounting film 310 is aligned and attached to thepad area PDA of the flexible display panel 100 using the secondalignment mark AM2 disposed in the second area A2 of the flexibledisplay panel 100. The circuit mounting film 310 may be aligned andattached to the pad area PDA of the flexible display panel 100 by usingthe second alignment mark AM2 and a reference point (not shown) of thecircuit mounting film 310.

The camera 810 may generate an alignment mark image using transmittedlight or reflected light according to a position of the lamp 830.

In one exemplary embodiment, the second alignment mark AM2 has astructure in which portions of a plurality of metal layers are stacked,so that the alignment mark image of the second alignment mark AM2generated by the transmitted light or the reflected light, may beclearly viewable.

The second alignment mark AM2 and the circuit mounting film 310 arealigned by using the alignment mark image. While the second alignmentmark AM2 and the circuit mounting film 310 are aligned with each other,the circuit mounting film 310 is attached to the flexible display panel100.

The flexible circuit board 330 may be mounted on the circuit mountingfilm 310 using the second alignment mark AM2 in substantially the samemanner as the assembling process of the circuit mounting film 310described above.

FIG. 9 is a cross-sectional view illustrating the flexible displayapparatus taken along line II-IP in FIG. 6A according to a secondassembling process.

Referring to FIG. 9, in the second assembling process, a window member400 is aligned and attached to the polarizing member 200 using a firstalignment mark AM1 disposed in the flexible display panel 100. Anadhesive film member may be disposed between the polarizing member 200and the window member 400 to attach the polarizing member 200 and thewindow member 400 to each other. The first alignment mark AM1 used inthe second assembling process may be the same first alignment mark AM1used in the first assembling process, without being limited thereto.

The camera 810 and the lamp 830 may be disposed under the flexibledisplay panel 100 since the light shielding part 410 of the windowmember 400 is above the flexible display panel 100.

The camera 810 generates a second alignment image using the reflectedlight reflected from the first alignment mark AM1 of the flexibledisplay panel 100.

In one exemplary embodiment, the first alignment mark AM1 has astructure in which portions of a plurality of metal layers are stacked,so that a sharpness of the second alignment image generated by thereflected light may be increased.

The first alignment mark AM1 and a second reference point RP2 of thewindow member 400 are aligned with each other using the second alignmentimage generated by the camera 810. While the first alignment mark AM1and the second reference point RP2 of the window member 400 are alignedwith each other, the window member 400 may be attached to the flexibledisplay panel 100. The second reference point RP2 of the window member400 may be defined at a location along the window member 400. The secondreference point RP2 of the window member 400 may be at an edge area ofthe window member 400.

FIG. 10 is a cross-sectional view illustrating the flexible displayapparatus taken along line II-IP in FIG. 6A according to a thirdassembling process.

Referring to FIG. 10, in the third assembling process, the protectivefilm 500 is aligned and attached to the second surface of the flexibledisplay panel 100 using the first alignment mark AM1 disposed in theflexible display panel 100. An adhesive film member may be disposedbetween the second surface of the flexible display panel 100 and theprotective film 500 to attach the flexible display panel 100 and theprotective film 500 to each other. The first alignment mark AM1 used inthe third assembling process may be the same first alignment mark AM1used in the second assembling process, without being limited thereto.

The camera 810 and the lamp 830 may be disposed under the flexibledisplay panel 100 due to the light shielding part 410 of the windowmember 400 above the flexible display panel 100.

In this case, the camera 810 generates a third alignment image using thereflected light reflected from the first alignment mark AM1 of theflexible display panel 100.

In one exemplary embodiment, the first alignment mark AM1 has astructure in which portions of a plurality of metal layers are stacked,such that a sharpness of the third alignment image generated by thereflected light may be increased.

The first alignment mark AM1 and a third reference point RP3 of theprotective film 500 are aligned with each other using the thirdalignment image generated by the camera 810. While the first alignmentmark AM1 and the third reference point RP3 of the protective film 500are aligned with each other, the protective film 500 may be attached tothe flexible display panel 100. The third reference point RP3 of theprotective film 500 may be defined at a location along the protectivefilm 500. The third reference point RP3 of the protective film 500 maybe at an edge area of the protective film 500.

FIG. 11 is a cross-sectional view illustrating the flexible displayapparatus taken along line in FIG. 6A according to a fourth assemblingprocess.

Referring to FIG. 11, in the fourth assembling process, the metal plate600 is aligned and attached to the protective film 500 using a secondalignment mark AM2 disposed in the flexible display panel 100. Anadhesive film member may be disposed between the protective film 500 andthe metal plate 600 to attach the protective film 500 and the metalplate 600 to each other.

The camera 810 and the lamp 830 may be disposed under the flexibledisplay panel 100 due to the light shielding part 410 and the metalplate 600 of the window member 400 above the flexible display panel 100.

The camera 810 generates a fourth alignment image using the reflectedlight reflected by the second alignment mark AM2 of the flexible displaypanel 100. The metal plate 600 is arranged to overlap the first area Alof the flexible display panel 100, e.g., the display area DA and theperipheral area PA. Thus, the metal plate 600 may be aligned withrespect to the stacked structure in FIG. 10 by using the secondalignment mark AM2 disposed in the second area A2.

In one exemplary embodiment, the second alignment mark AM2 has astructure in which portions of a plurality of metal layers are stacked,so that a sharpness of the fourth alignment image generated by thereflected light may be increased.

The second alignment mark AM2 and a fourth reference point RP4 of themetal plate 600 are aligned with each other using the fourth alignmentimage generated by the camera 810. While the second alignment mark AM2and the fourth reference point RP4 of the metal plate 600 are alignedwith each other, the metal plate 600 may be attached to the flexibledisplay panel 100. The fourth reference point RP4 of the metal plate 600may be defined at a location along the metal plate 600. The fourthreference point RP4 of the metal plate 600 may be at an edge area of themetal plate 600.

FIG. 12 is a cross-sectional view illustrating the flexible displayapparatus taken along line IV-IV′ in FIG. 6B according to a fifthassembling process.

Referring to FIG. 12, in a fifth assembling process, the stackedstructure in FIG. 11 is bent to dispose the second area A2 of theflexible display panel 100 facing the second surface of the flexibledisplay panel 100.

The metal plate 600 may include a first surface facing and at which themetal plate 600 is attached to the protective film 500, and a secondsurface opposite the first surface. The flexible display panel 100 maybe bent to dispose the second area A2 facing the second surface of themetal plate 600.

The camera 810 and the lamp 830 may be disposed under the flexibledisplay panel 100, at a same side of the stacked structure in FIG. 12 atwhich the metal plate 600 is disposed.

The camera 810 generates a fifth alignment image using the reflectedlight reflected by the second alignment mark AM2 of the flexible displaypanel 100. The second alignment mark AM2 used in the fifth assemblingprocess may be the same second alignment mark AM1 used in the fourthassembling process, without being limited thereto.

In one exemplary embodiment, the second alignment mark AM2 has astructure in which portions of a plurality of metal layers is stacked,so that a sharpness of the fifth alignment image generated by thereflected light may be increased.

The second alignment mark AM2 of the flexible display panel 100 isaligned with a bending reference point RP5 in an area of the stackedstructure in FIG. 12, using the fifth alignment image displayed on thecamera 810. A bending reference point RP5 may be defined relative to thesecond surface of the metal plate 600, without being limited thereto.The stacked structure of FIG. 11 may be bent dispose the second area A2of the flexible display panel 100 at an accurate position relative tothe metal plate 600 and to avoid multiple bending attempts therebyreducing or effectively preventing defects such as cracks in the fan-outsignal lines in the second area A2 which may also be bent in the fifthassembling process.

A module assembly of the flexible display apparatus may be completed bythe above assembling processes.

According to one or more of the exemplary embodiments, the flexibledisplay apparatus includes alignment marks each having stacked portionsof a plurality of metal layers fabricated from the same plurality ofmetal layers used in manufacturing processes of the thin film transistorand the touch sensor. In the module-assembling processes of the flexibledisplay apparatus, a clear alignment mark image may be obtained by thealignment marks having a structure in which portions of a plurality ofmetal layers are stacked. Therefore, an accuracy of themodule-assembling processes may be improved.

One or more exemplary embodiments may be applied to a display device andan electronic device which has the display device. One or more exemplaryembodiments, for example, may be applied to a computer monitor, alaptop, a digital camera, a cellular phone, a smart phone, a smart pad,a television, a personal digital assistant, a portable multimedia player(“PMP”), a MP3 player, a navigation system, a game console, a videophone, etc.

The foregoing is illustrative of the invention and is not to beconstrued as limiting thereof. Although a few exemplary embodiments ofthe invention have been described, those skilled in the art will readilyappreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of the invention. Accordingly, all such modifications areintended to be included within the scope of the invention as defined inthe claims. In the claims, means-plus-function clauses are intended tocover the structures described herein as performing the recited functionand not only structural equivalents but also equivalent structures.Therefore, it is to be understood that the foregoing is illustrative ofthe invention and is not to be construed as limited to the specificexemplary embodiments disclosed, and that modifications to the disclosedexemplary embodiments, as well as other exemplary embodiments, areintended to be included within the scope of the appended claims. Theinvention is defined by the following claims, with equivalents of theclaims to be included therein.

What is claimed is:
 1. A flexible display apparatus comprising: aflexible display panel comprising: a flexible substrate comprising aplastic layer, a display area of the flexible substrate comprising athin film transistor, an organic light emitting layer, and a sensorelectrode on the flexible substrate, and a peripheral area of theflexible substrate adjacent to the display area, the peripheral areacomprising a first alignment mark in which respective portions of twometal layers are stacked; a window on a first surface of the flexibledisplay panel, the window comprising a reference point defined along thewindow, a transmissive window corresponding to the display area and alight shielding part corresponding to the peripheral area; and aprotective film on a second surface of the flexible display panel whichis opposite to the first surface thereof, the protective film comprisinga reference point defined along the protective film, wherein the firstalignment mark is aligned with the reference point of the window andwith the reference point of the protective film.
 2. The flexible displayapparatus of claim 1, wherein the flexible display panel furthercomprises: a signal line which is in the display area and to which adisplay signal is provided, an extension area extended from theperipheral area in a direction away from the display area, and a pad inthe extension area, through which the display signal is transmitted fromoutside the flexible display panel to the signal line in the displayarea.
 3. The flexible display apparatus of claim 2, wherein theextension area of the flexible display panel comprises a secondalignment mark in which respective portions of two metal layers arestacked, the two metal layers of the first alignment mark beingdifferent from the two metal layers of the second alignment mark.
 4. Theflexible display apparatus of claim 2, further comprising: a flexiblecircuit board from which the display signal is provided to the flexibledisplay panel, and a circuit mounting film connected to the flexiblecircuit board and to the pad in the extension area the flexible displaypanel, and through which the display signal from the flexible circuitboard is transmitted to the pad.
 5. The flexible display apparatus ofclaim 4, further comprising a metal plate facing the second surface ofthe flexible display panel, wherein the flexible display panel which isbent disposes the metal plate between the extension area of the flexibledisplay panel and the protective film on the second surface of theflexible display panel.
 6. The flexible display apparatus of claim 5,wherein the second alignment mark is aligned with a reference point ofeach of the circuit mounting film, the flexible circuit board and themetal plate, which is respectively defined along the circuit mountingfilm, the flexible circuit board and the metal plate.
 7. The flexibledisplay apparatus of claim 1, further comprising a polarizing memberbetween the flexible display panel and the window.
 8. The flexibledisplay apparatus of claim 7, wherein the first alignment mark isfurther aligned with a reference point of the polarizing member which isdefined along the polarizing member.
 9. The flexible display apparatusof claim 1, wherein the display area of the flexible display panelincludes a folding axis about which the flexible display panel isbendable.
 10. The flexible display apparatus of claim 3, wherein thefirst alignment mark and the second alignment mark each comprise aportion of a first metal layer, a portion of a second metal layer, aportion of a third metal layer and a portion of a fourth metal layersequentially which are stacked on the flexible substrate.
 11. Theflexible display apparatus of claim 3, wherein the thin film transistorcomprises a gate electrode and a source electrode, the sensor electrodeincludes a first touch electrode and a second touch electrode, the gateelectrode, the first alignment mark and the second alignment mark eachinclude respective portions of a same first metal layer, the sourceelectrode, the first alignment mark and the second alignment mark eachinclude respective portions of a same second metal layer, the firsttouch electrode, the first alignment mark and the second alignment markeach include respective portions of a same third metal layer, and thesecond touch electrode, the first alignment mark and the secondalignment mark each include respective portions of a same fourth metallayer.
 12. The flexible display apparatus of claim 1, wherein theflexible substrate comprises a first transparent plastic layer, aplastic layer, and a second transparent plastic layer that aresequentially stacked.
 13. A method of assembling a flexible displayapparatus, the method comprising: providing a flexible display panelcomprising: a flexible substrate comprising a plastic layer, a displayarea of the flexible substrate comprising a thin film transistor, anorganic light emitting layer, and a sensor electrode on the flexiblesubstrate, and a peripheral area of the flexible substrate adjacent tothe display area, the peripheral area comprising a first alignment markin which respective portions of two metal layers are stacked, attachinga polarizing member on a first surface of the flexible display panel byusing the first alignment mark; attaching a window on the first surfaceof the flexible display panel by using the first alignment mark; andattaching a protective film on a second surface of the flexible displaypanel which is opposite to the first surface thereof, by using the firstalignment mark.
 14. The method of claim 13, wherein the attaching thepolarizing member comprises: providing the polarizing member on theflexible display panel and generating an alignment image of the firstalignment mark by using light which is transmitted or reflected at anarea of the flexible display at which the first alignment mark isprovided, and aligning the first alignment mark and a reference point ofthe polarizing member which is defined along the polarizing member, byusing the alignment image of the first alignment mark.
 15. The method ofclaim 13, wherein the attaching the window comprises: providing thewindow on the flexible display panel and generating an alignment imageof the first alignment mark by using light which is reflected at an areaof the flexible display at which the first alignment mark is provided,and aligning the first alignment mark and a reference point of thewindow which is defined along the window, by using the alignment imageof the first alignment mark.
 16. The method of claim 13, wherein theattaching a protective film comprises: providing the protective film onthe flexible display panel and generating an alignment image of thefirst alignment mark by using light which is reflected at an area of theflexible display at which the first alignment mark is provided, andaligning the first alignment mark and a reference point of theprotective film which is defined along the protective film, by using thealignment image of the first alignment mark.
 17. The method of claim 13,wherein the flexible display panel further comprises: a signal linewhich is in the display area and to which a display signal is provided,an extension area extended from the peripheral area in a direction awayfrom the display area, a pad in the extension area, through which thedisplay signal is transmitted from outside the flexible display panel tothe signal line in the display area, and a second alignment mark whichis in the extension area and in which respective portions of two metallayers are stacked, the two metal layers of the first alignment markbeing different from the two metal layers of the second alignment mark,and the method further comprises: attaching a circuit mounting film onthe extension area using the second alignment mark; and attaching ametal plate on the protective film using the second alignment mark. 18.The method of claim 17, wherein the attaching the circuit mounting filmcomprises: providing the circuit mounting film on the flexible displaypanel and generating an alignment image of the second alignment mark byusing light which is transmitted or reflected at an area of the flexibledisplay at which the second alignment mark is provided, and aligning thesecond alignment mark and a reference point of the circuit mounting filmwhich is defined along the circuit mounting film, by using the alignmentimage of the second alignment mark.
 19. The method of claim 17, whereinthe attaching the metal plate comprises: providing the metal plate onthe flexible display panel and generating an alignment image of thesecond alignment mark by using light which is reflected at an area ofthe flexible display at which the second alignment mark is provided, andaligning the second alignment mark with a reference point of the metalplate which is defined along the metal plate, by using the alignmentimage of the second alignment mark.
 20. The method of claim 17, furthercomprising: bending the extension area of the flexible display panelhaving the metal plate attached to the protective film, toward the metalplate; generating an alignment image of the second alignment mark byusing light which is reflected at an area of the flexible display atwhich the second alignment mark is provided, and aligning the secondalignment mark with a bending reference point defined along the metalplate, by using the alignment image of the second alignment mark.